The leather looks to be a 2nd or 3rd grade hide. You would want to use a 1st grade hide to get the smoothest and best quality. Having said that you can try a few different things to smooth the leather. The first is to soak it well in water and clamp it tightly between two smooth boards for a day or so till it dries. You'll need to give it a liberal dose of a leather treatment to replace some of the lost oils.
Another method to make the paddle strop up (I assume you are making a paddle again) and then sanding the leather with wet and dry until it is nice and smooth.
And another again is to simply give the leather a good stretching. Give the leather a good dose of leather treatment (not straight neats-foot oil. Jay-el or Dubbin or something similar is better), clamp one end or nail it down so that it won't move. Using a nice big screwdriver or similar smooth rod type object of decent size for the task, put a turn of the leather around it pull the unsecured end with you hand so that it tightens the turn around your screwdriver. Hold ig the handle of the screwdriver with you remaining hand so that it is forming 90' with the leather, begin pushing and pulling the screwdriver up and down the leather.
Hope some of this helps, But you will probably choose to buy a cheap strop instead...Might be getting into the too complicated basket for most people now.
That's some pretty rough cuttin' there mate...:D
Mick